Positive displacement pump



Nov. 30, 1965 N. G. KLING 3,220,351

POSITIVE DISPLACEMENT PUMP Filed May 28, 1963 14 a y j ,5

I FIG.3

' INVENTOR. 72 73 65 NELSON G. KLING ATTORNEY United States Patent 3,220,351 POSITIVE DISPLACEMENT PUMP Nelson G. Kling, Ringwood, N.J., assignor to Technicon Chromatography Corporation, Chauncey, N.Y., a corporation of New York Filed May 28, 1963, Ser. No. 283,928 3 Claims. (Cl. 103-153) This invention relates to pumps and, more particularly, to pumps of the positive displacement type intended primarily for, but not limited to, pumping small volumes of liquid.

One object of the invention is the provision of improved inlet and outlet valve means for the pump and, more particularly, the provision of valve means which has an improved anti-corrosion characteristic and which has improved liquid sealing action in its closed conditions.

Another object of the invention is to provide valve means wherein a plurality of valves are employed at both the inlet and the outlet of the pump with a single unitary valve body for the plurality of valves at the in let of the pump and with a single valve body for the plurality of valves at the outlet of the pump.

Another object is to provide a pump wherein the piston is corrosion-resistant to various liquids.

A further object is the provision of a pump which is especially advantageous for pumping bufier or eluting liquids to chromatography columns for the stripping operation.

A yet further object of the invention is generally to provide a pump of the indicated type of improved con struction and reliability in operation.

The above and other objects, features and advantages of the invention will be fully understood from the following description considered in connection with the accompanying drawings which are illustrative of the presently preferred embodiment of the invention.

In the drawings:

FIG. 1 is a sectional view of the pump;

FIG. 2 is a sectional view on a larger scale on the line 22 of FIG. 1; and

FIG. 3 is a sectional view on a greatly enlarged scale on the line 33 of FIG. 2.

Referring now to the drawings in detail, the pump comprises the housing 10, which is preferably made of stainless steel or other material which is resistant to corrosion by various liquids for which the pump is used. Said housing comprises a cylindrical bore 12 for the cylindrical piston or plunger 14, threaded bores 16 and 18 for the valve housing nipples 20 and 22, respectively, which are secured in said bores by being screwed therein, and a bore 24 which provides a passage for the liquid into the cylinder, at the opening 25 in said passage intermediate the opposite end openings of said passage, and for the subsequent passage of liquidout of the cylinder in the pumping operation. The housing is shown mounted on a support 26, said housing having an integral lateral extension 28 which has a snug fit in the opening 30 of said support. Said housing is secured releasably in position on said support by a threaded nut 32 which engages an externally threaded part of housing extension 28 and is operable in conjunction with the side '64 of the housing to clamp said housing to said support. A non-circular pin 36 engaging the housing 10 and the 3,220,351 Patented Nov. 30, 1965 support 26 in openings therein is provided to prevent turning of the housing bodily when the nut 32 is rotated for engagement with the adjacent side of support 26.

Pursuant to the present invention, the piston 14 is made of corrosion-resistant material such as, for example, tungsten carbide and is secured to the cylindrical piston actuating stem 38 in any suitable way, preferably by soldering an end portion of piston 14 in a socket 40 provided in the forward end of actuating stem 38. A guide bushing 42, formed of anti-friction material to obviate the need for lubrication, is provided for said piston actuating stem. Said guide bushing 42 has a tight fit in sleeve 44, which is provided with a flange 46 at its outer end for engagement by the nut 48 which "is threaded on extension 28 of housing 10 for holding said sleeve in position. A fluid sealing ring 50 is provided to form a fluid-tight joint between the forward end of sleeve 44 and the confronting surface portion of -cylinder 12 and around the piston 14. Nut 48 is provided with an opening 52 for the movement of the piston actuating stem 38 by the actuating means (not shown), which is effective to reciprocate said stem and the piston 14 in a well known way for the intake and output strokes of the piston.

The valve means of the present invention will now be described with particular reference to the enlarged view represented by FIG. 2 and the still larger view represented by FIG. 3. The inlet valve means and the outlet valve means are the same and are designated by the reference numeral 54, each of said valve means having a close fit within its companion housing 18 and 20, respectively. Valve means 54 comprises a valve body 56, formed of Teflon or other suitable corrosion-resistant plastic, and is provided with a plurality of ball valves 58 and 60 which are formed of corrosion-resistant material, for example stainless steel or tungsten carbide. A plurality of valves are usually provided in pumps of the type to which the present invention relates as a precaution against the leakage of liquid when the valves are seated in their closed positions. The annular valve seats for the balls 58 and 60 are indicated at 62 and 64, respectively.

Pursuant to the present invention, ball valve 60 is larger than ball valve 58 and the seats for said ball valves are correspondingly dimensioned so that the valve body 56 can be made in one piece and yet be provided with two valve seats. The outlet opening 66 in outlet valve housing nipple 22 is square so that liquid may be discharged through the outlet valve even though the valve ball 60 abuts the inner surface of nipple 22 around outlet opening 66, which might happen during the output stroke of piston 14. Similarly, passage 24, or at least its end adjacent ball valve 60 of the inlet valve means, is square so that liquid may enter said passage 24 of the cylinder 12 during the intake stroke of the piston even though the ball valve 60 of the inlet valve means might abut the adjacent surface of the valve housing at the inlet end of passage 24.

The valve body 56 is provided with fluid sealing means 68 and 70 at its opposite ends respectively. Referring to FIG. 3, the sealing member comprises the flexible annular flange 72 pressed outwardly by a toroidal metal spring 74 for fluid-tight sealing engagement with the inner end of the nipple 22, in the case of the outlet valve control means, or with the wall of passage 24 at the inlet end thereof, in the case of the valve control means for the inlet. Said flange 72 has a medial circumferentially extending convex portion 76 for improving the fluid seal. It will be noted that the flange of the fluid seal 70 defines a circular opening 78 for the passage of fluid through the valve body when the valves 58 and 60 are unseated from the valve seats 62 and 64, respectively. Spring 74 can be readily inserted in the valve housing through opening 78 since flange 72 is flexible. It is to be noted that flange 76 is not only pressed into fluid sealing engagement with the confronting part of the nipple 22 or with the confronting surface of the housing around the passage 24, in the case of the inlet valve, but is also acted upon by the fluid pressure on the inner side of the flange. As shown by FIG. 3, the fluid seal 68 is of the same construction as the fluid seal 70 except in respect to its size.

The operation of the pump and the inlet and outlet valve means is thought to be clear from the above description. In summary, the operation is as follows: When the piston 14 is moved for its intake stroke, to the right, viewing FIG. 1, liquid is drawn into the valve body of the inlet valve through nipple 20, valves 58 and 60 being unseated by the suction incident to the intake stroke of the piston. Fluid passes through the valve body into the passage 24 and from the latter through the opening 25 to the cylinder 12, outlet valves 58 and 69 remaining closed since the pressure in nipple 22 is greater than the pressure in passage 24 during the intake stroke of the piston. Upon completion of the intake stroke of the piston 14, the inlet valve means closes automatically and the piston is moved in the opposite direction for its liquid output stroke, that is to the left, viewing FIG. 1, for expelling the liquid from the cylinder 12 into the passage 24 and from the latter through the outlet valve body 54 and through the opening 66 of the outlet nipple 22, valves 58 and 60 at the inlet nipple 20 being closed because the pressure in passage 24 is then higher than the pressure in the fluid in inlet nipple 20. It will be readily understood that valves 58 and 60 act as check valves since they are opened by the pressure of the fluid when flow of the fluid is in one direction and are closed by fluid pressure acting in the opposite direction.

Thus it is seen that the pump of the above described construction is well adapted to accomplish the objects of the invention. It will be understood however that While I have shown and described the preferred embodiment of my invention, it may be embodied otherwise than as herein shown or described and that in the illustrated embodiment certain changes in the details of construction and in the form and arrangement of parts may be made without departing from the underlying idea or principles of this invention within the scope of the appended claims.

What I claim is:

1. In a pump having a cylinder, a piston reciprocable in said cylinder, fluid inlet means, fluid outlet means, fluidpassage means in communication, at opposite ends thereof, with said inlet means and said outlet means, respectively, said fluid-passage means having an opening intermediate said opposite ends in communication with said cylinder for the flow of fluid into said cylinder from said inlet means when the piston moves in one direction followed by flow of fluid out of said cylinder and through said outlet means when the piston moves in the opposite direction, valve means for controlling said flow of the fluid into and out of said cylinder through said inlet and outlet means, respectively, comprising valve bodies each having a passage in communication with said opposite ends, respectively, of said passage means, each of said valve bodies having at least one valve seat and a companion ball valve, and having at its opposite ends resiliently flexible fluid sealing means providing fluid seals around the openings at the opposite ends, respectively,

of said fluid passage of the valve body, said resiliently flexible fluid sealing means of the valve body comprising flexible annular flanges in fixed relationto the valve body at said opposite ends, respectively, of the valve body, and spring means disposed internally of the valve body in engagement with said annular flanges around the opening at each end of said passage of the valve body.

2. In a pump having a cylinder, a piston reciprocable in said cylinder, fluid inlet means, fluid outlet means, fluidpassage means in communication, at opposite ends thereof, with said inlet means and said outlet means, respectively, said fluid-passage means having an opening intermediate said opposite ends in communication with said cylinder for the flow of fluid into said cylinder from said inlet means when the piston moves in one direction followed by flow of fluid out of said cylinder and through said outlet means when the piston moves in the opposite direction, valve means for controlling said flow of the fluid into and out of said cylinder through said inlet and outlet means, respectively, comprising valve bodies each having a passage in communication with said opposite ends, respectively, of said passage means, each of said valve bodies being formed in one piece and having a plurality of valve seats spaced from each other axially of said passage therein, and ball valves for said seats, respectively, said passage having axially extending parts of different diameters, respectively, and said valve seats and companion ball valves having correspondingly different diameters, a first part of the passage which has a larger diameter than another part of the passage extending from one end of the valve body, in a direction toward the opposite end of the valve body, to one of said valve seats and a part of the passage which has a smaller diameter than that of said first part extending from said one of the valve seats, in said direction, to another of said valve seats, said one of the valve seats and its companion ball Valve being larger in diameter than said other of the valve seats and its companion ball valve, each of said valve bodies having at its opposite ends resiliently flexible fluid sealing means providing fluid seals around the openings at the opposite ends, respectively, of said fluid passage of the valve body, said resiliently flexible fluid sealing means of the valve body comprising flexible annular flanges in fixed relation to the valve body at said opposite ends, respectively, of the valve body, and spring means disposed internally of the valve body in engagement with said annular flanges around the opening at each end of said passage of the valve body.

3. A pump having a cylinder, a piston reciprocable in said cylinder, fluid inlet means, fluidoutlet means, and fluid-passage means in communication, at opposite ends thereof, with said inlet means and said outlet means, respectively, said fluid-passage means having an opening intermediate said opposite ends in communication with said cylinder for the flow of fluid into said cylinder from said inlet means when the piston moves in one direction followed by flow of fluid out of said cylinder and through said outlet means when the piston moves in the opposite direction, said piston being formed of corrosion-resistant material, and valve means for controlling said flow of the fluid into and out of said cylinder through said inlet and outlet means, respectively, comprising valve bodies each having a passage in communication with said opposite ends, respectively, of said passage means, each of said valve bodies having at least one valve seat and a companion ball valve, and having at its opposite ends resiliently flexible fluid sealing means providing fluid seals around the openings at the opposite ends, respectively, of said fluid passage of the valve body, said resiliently flexible fluid sealing means of the valve body comprising flexible annular flanges in fixed relation to the valve body at said opposite ends, respectively, of the valve body, and spring means disposed internally of the valve body in engagement with said annular flanges 5 6 around the opening at each end of said passage of the 3,073,256 1/1963 Browne et a1 103153 X valve body, 3,125,963 3/1964 Whitley et -a1 103-153 References Cited by the Examiner 736 330 6/I 9 EZ G PATENTS ermany. UNITED STATES PATENTS 5 926,093 5/1963 Great Britain. 482,230 9/1892 Crimmel 137533.11 X

Giraudeau J. Prllnary Exal'nlner. 2,771,845 11/1956 Eagan 102153 WARREN E. COLEMAN, ROBERT M. WALKER,

Examiners. 

1. IN A PUMP HAVING A CYLINDER, A PISTON RECIPROCABLE IN SAID CYLINDER, FLUID INLET MEANS, FLUID OUTLET MEANS, FLUIDPASSING MEANS IN COMMUNICATION, AT OPPOSITE ENDS THEREOF, WITH SAID INLET MEANS AND SAID OUTLET MENS, RESPECTIVELY, SAID FLUID-PASSAGE MEANS HAVING AN OPENING INTERMEDIATE SAID OPPOSITE ENDS IN COMMUNICATION WITH SAID CYLINDER FOR THE FLOW OF FLUID INTO SAID CYLINDER FROM SAID INLET MEANS WHEN THE PISTON MOVES IN ONE DIRECTION FOLLOWED BY FLOW OF FLUID OUT OF SAID CYLINDER AND THROUGH SAID OUTLET MEANS WHEN THE PISTON MOVES IN THE OPPOSITE DIRECTION, VALVE MEANS FOR CONTROLLING SAID FLOW OF THE FLUID INTO AND OUT OF SAID CYLINDER THROUGH SAID INLET AND OUTLET MEANS, RESPECTIVELY, COMPRISING VALVE BODIES EACH HAVING A PASSAGE IN COMMUNICATION WITH SAID OPPOSITE ENDS, RESPECTIVELY, OF SAID PASSAGE MEANS, EACH OF SAID VALVE BODIES HAVING AT LEAST ONE VALVE SEAT AND A COMPANION BALL VALVE, AND HAVING AT ITS OPPOSITE ENDS RESILIENTLY FLEXIBLE FLUID SEALING MEANS PROVIDING FLUID SEALS AROUND THE OPENINGS AT THE OPPOSITE ENDS, RESPECTIVELY, OF SAID FLUID PASSAGE OF THE VALVE BODY, SAID RESILIENTLY FLEXIBLE FLUID SEALING MEANS OF THE VALVE BODY COMPRISING FLEXIBLE ANNULAR FLANGES IN FIXED RELATION TO THE VALVE BODY AT SAID OPPOSITE ENDS, RESPECTIVELY, OF THE VALVE BODY, AND SPRING MEANS DISPOSED INTERNALLY OF THE VALVE BODY IN ENGAGEMENT WITH SAID ANNULAR FLANGE AROUND THE OPENING AT EACH END OF SAID PASSAGE OF THE VALVE BODY. 